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From: Togan Muftuoglu (toganmusers.sourceforge.net)
Date: Wed Sep 26 2001 - 14:48:38 CDT

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    * Michael Neumann; <mnsyk.de> on 26 Sep, 2001 wrote:
    > Hi all,
    >
    > I use iptables as a firewall on my local machine to filter any incoming
            ^^^^^^^^^^^
    > filtered. I have tried with DENY and REJECT but got the same report.
    >

    DENY is now DROP

    the below is from the SENTRY Firewall CD

            $IPTABLES -N CHECK_FLAGS
            $IPTABLES -F CHECK_FLAGS

       ##------------------------------------------------------------------------##
       ## NMAP FIN/URG/PSH
            $IPTABLES -A CHECK_FLAGS -p tcp --tcp-flags ALL FIN,URG,PSH -m limit \
                    --limit 5/minute -j LOG --log-level $LOG_LEVEL --log-prefix "NMAP-XMAS:"
            $IPTABLES -A CHECK_FLAGS -p tcp --tcp-flags ALL FIN,URG,PSH -j DROP
       ##------------------------------------------------------------------------##

       ##------------------------------------------------------------------------##
       ## SYN/RST
            $IPTABLES -A CHECK_FLAGS -p tcp --tcp-flags SYN,RST SYN,RST -m limit \
                    --limit 5/minute -j LOG --log-level $LOG_LEVEL --log-prefix "SYN/RST:"
            $IPTABLES -A CHECK_FLAGS -p tcp --tcp-flags SYN,RST SYN,RST -j DROP
       ##------------------------------------------------------------------------##

       ##------------------------------------------------------------------------##
       ## SYN/FIN -- Scan(probably)
            $IPTABLES -A CHECK_FLAGS -p tcp --tcp-flags SYN,FIN SYN,FIN -m limit \
                    --limit 5/minute -j LOG --log-level $LOG_LEVEL --log-prefix "SYN/FIN:"
            $IPTABLES -A CHECK_FLAGS -p tcp --tcp-flags SYN,FIN SYN,FIN -j DROP
       ##------------------------------------------------------------------------##

       ##------------------------------------------------------------------------##
       ## Make some types of port scans annoyingly slow, also provides some
       ## protection against certain DoS attacks. The rule in chain KEEP_STATE
       ## referring to the INVALID state should catch most TCP packets with the
       ## RST or FIN bits set that aren't associate with an established connection.
       ## Still, these will limit the amount of stuff that is accepted through our
       ## open ports(if any). I suggest you test these for your configuration before
       ## you uncomment them, as they could cause problems.

    # $IPTABLES -A CHECK_FLAGS -m limit --limit 5/second -p tcp --tcp-flags ALL RST -j ACCEPT
    # $IPTABLES -A CHECK_FLAGS -m limit --limit 5/second -p tcp --tcp-flags ALL FIN -j ACCEPT
    # $IPTABLES -A CHECK_FLAGS -m limit --limit 5/second -p tcp --tcp-flags ALL SYN -j ACCEPT
       ##------------------------------------------------------------------------##

    -- 
    Togan Muftuoglu
    

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